Integrated circuits are used in many portable electronic products, such as cell phone, portable computers, voice recorders, etc. as well as in many larger electronic systems, such as cars, planes, industrial control systems, etc. Across virtually all applications, there continues to be demand for reducing the size and increasing performance of the devices. The intense demand is no more visible than in portable electronics that have become so ubiquitous.
Wafer manufacturing strives to reduce transistor or capacitor feature size in order to increase circuit density and enhance functionality. Device geometries with sub-micron line widths are so common that individual chips routinely contain millions of electronic devices. Reduced feature size has been quite successful in improving electronic systems, and continuous development is expected in the future. However, significant obstacles to further reduction in feature size are being encountered. These obstacles include defect density control, optical system resolution limits, and availability of processing material and equipment. Attention has therefore increasingly shifted to semiconductor packaging as a means to fulfill the relentless demands for enhanced system performance.
As multi-die and package stacking becomes more and more common, known good die issues are becoming critical for cost saving issues and throughput yield. For example, in a four-die stack package, a single die can make the whole package unusable even if the other three dies are fully functional. One of the ways to overcome this problem is by using package stacking which can overcome known good die issues since die functionality can be checked after being packaged and before being placed on top of another known good package. On the other hand, miniaturization is forcing package profiles to become thinner and thinner which may become a road block to widespread use of package stacking due to the larger height profiles compared to die stacking.
Thus a need still remains for an integrated circuit package system to provide increasing density without sacrificing reliability, yield and height profiles. In view of the increasing demand for density of integrated circuits and particularly portable electronic products, it is increasingly critical that answers be found to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.